Semiconductor devices are currently in widespread use in a variety of electronic components. Semiconductor devices may be used for a variety of reasons, such as to retain information, as in a non-volatile memory device, or to perform a calculation, such as in a microprocessor or in a digital signal processor. Semiconductor devices typically have a protective housing that houses semiconductor circuitry within the semiconductor device and leads connected with the semiconductor circuitry for connecting the semiconductor circuitry to a circuit board. Sometimes, a semiconductor device may fail due to a defect either in the manufacturing process or the design process. To determine why a particular semiconductor device has failed, the semiconductor device requires testing. In order to test the semiconductor device, the device needs to be decapped, that is, a portion of the top side of the protective housing needs to be removed in order to expose the semiconductor circuitry within.
Once decapped, the semiconductor device is then placed in a socket, such as the IC354 Socket manufactured by Yamaichi Electronics CO., LTD., of Tokyo, Japan. Once placed in the socket, the semiconductor device remains at a set distance from the top of the socket. The socket is attached to a low-noise printed circuit board which is connected to testing instruments. Once the printed circuit board is connected to the tester, a pico-probe, which is connected to the tester, may be used to probe and test the connections within the semiconductor circuitry. Since the length of the pico-probe is fixed, the distance from the top of the socket makes it more difficult for the pico-probe to connect with and probe the semiconductor circuitry once the semiconductor device is within the socket. Thus, there is a need for a device which can effectively be used to mount a semiconductor device to a circuit board for testing with a probe.
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims. By way of introduction, the preferred embodiments described below relate to a leadless socket for mounting a semiconductor device to a circuit board for testing. The semiconductor device includes semiconductor circuitry and leads to connect the semiconductor circuitry to the circuit board. Additionally, the semiconductor device is decapped so that at least a portion of the semiconductor circuitry is exposed. The leadless socket includes a frame and a fastener. The frame is adapted to mate with the semiconductor device, and forms an opening for accessing the semiconductor circuitry and an edge surface for receiving the semiconductor device. The fastener is connected with the frame for removably connecting the frame to the circuit board. By using a frame instead of a socket, the distance to the semiconductor device once the device is mounted to the circuit board, and particularly the top side of the semiconductor device, can be reduced so that the device may be tested using a probe, such as a pico-probe.
The preferred embodiments further relate to a method for mounting a semiconductor device to a circuit board for testing. The semiconductor device includes semiconductor circuitry and leads, and the semiconductor device is decapped so that at least a portion of the semiconductor circuitry is exposed along a top side of the semiconductor device. The circuit board includes traces along a top side of the circuit board.
The method includes forming a frame that mates with the semiconductor device. The frame has a top surface opposed to a bottom surface and an edge surface parallel to and recessed into the bottom surface. The frame forms an opening from the top surface to the edge surface for accessing the semiconductor circuitry. Additionally, the size of the opening is less than the size of the semiconductor device. The method further includes placing the top side of the semiconductor device in the frame against the edge surface so that the semiconductor circuitry is accessible through the opening. Moreover, the method includes fastening the frame and the semiconductor device to the circuit board, wherein the bottom surface faces the top side of the circuit board.
The preferred embodiments further relate to a leadless socket for mounting a semiconductor device to a circuit board for testing. The semiconductor device includes semiconductor circuitry and leads. The semiconductor device is decapped so that at least a portion of the semiconductor circuitry is exposed along a top side of the semiconductor device. Additionally, the circuit board includes traces along a top side of the circuit board. The leadless socket includes a frame that mates with the semiconductor device. The frame has a top surface opposed to a bottom surface and an edge surface parallel to and recessed into the bottom surface. The frame also forms an opening from the top surface to the edge surface for accessing the semiconductor circuitry. The size of the opening is less than the size of the semiconductor device. Further aspects and advantages of the invention are discussed below in conjunction with the preferred embodiments.